12 BOTANICAL GAZETTE [JULY 
gradually diminished, and finally ceased about 8:00 A.M. The male 
gametes continue in the motile condition for more than 24 hours, 
while the female gametes retain their motility for scarcely one 
hour and sometimes only for a few seconds. Toward the end of the 
motile condition, the movement of the gametes becomes sluggish, the 
cilia become coalescent with the protoplast, and finally the shape 
of the gametes becomes spherical. Even after the gametes have 
assumed the spherical form the polar organization in regard to the 
distribution of plastids is not lost. The area of granular cytoplasm 
with no plastids remains for a considerable time. From observation 
of the living material, it is evident that the formation of the wall, its 

a Fic. 9.—Portions of thallus showing the ori 
Initials: @ and b, 2 and 3 lay 
each case are female gametangium initials, 
5 gin of the female gametangium 
ers of superficial cells Tespectively, outermost of which in 
The male gametes while swimmi 
the female gametes which Nia we Pecome attached to 
l 
Numerous m © moving actively or sluggishly. 
pets - Sunyige however, after Swimming for a agen 
sad than hse to come into contact with the female gametes 
ovement ceases and the cilia fuse with the plasma 
